WO2012138145A2 - Polyester binder resin for coating, and coating composition containing same - Google Patents

Abstract

Disclosed are a polyester binder resin for coating, and a coating composition containing the same, wherein lactic acid or a compound derived therefrom and isosorbide are copolymerized, and thus the content of biomass-derived compounds is high and coating hardness, contamination resistance, hydrolysis resistance and processability are excellent. The polyester binder resin for coating is obtained by copolymerizing a dibasic acid component; a diol component containing 1-60 mol of isosorbide with respect to the total diol components; and 1-50 wt% of lactic acid or a compound derived therefrom with respect to the total resin polymerization reactants, and has the structure in which a dibasic moiety derived from the dibasic acid component, a diol moiety derived from the diol component, and a hydroxy monobasic acid moiety derived from said lactic acid or a compound derived therefrom are repeated.

Description

Polyester binder resin for coating and coating composition containing same

The present invention relates to a polyester binder resin for coating and a coating composition containing the same, and more particularly, lactic acid or a compound derived therefrom and isosorbide to copolymerize a high biomass-derived compound, as well as coating film hardness, The present invention relates to a polyester binder resin for coating having excellent stain resistance, hydrolysis resistance, processability, and the like, and a coating composition containing the same.

In general, the coating composition (paint) should not only have excellent adhesion to metals, polymer films and other adherends, but also have excellent coating film hardness, stain resistance, hydrolysis resistance, and the like. Coating compositions using binders such as alkyd resins, vinyl resins, silicone resins, etc. are excellent in hardness, fouling resistance, hydrolysis resistance, etc., but have poor workability and thus have many limitations and difficulties in practical application. In order to overcome this disadvantage, the use of a high molecular weight polyester resin as a coating binder is considered. However, although the high molecular weight polyester resin binder having a linear linear structure has excellent workability, coating film hardness, fouling resistance, hydrolysis resistance, etc. are undesirable.

In order to improve the physical properties of polyester resin binders, Japanese Patent Laid-Open No. Hei 2- 209979 discloses a method of using an alkylene oxide group adduct of bisphenol-A. This method improves the processability to some extent by increasing the molecular weight of the polyester resin, and improves the adhesion and hardness with the metal material, but due to the increase of ether bonds due to the introduction of excess bisphenol-A structure, It is lowered, the weather resistance of the coating film is lowered, the glass transition temperature of the resin is 70 ℃ or less, there is a disadvantage that the hardness of the coating film is low. Further, Japanese Patent Laid-Open No. 62-21830 discloses a polyester resin containing terephthalic acid and alkylene glycol as main components, which have excellent workability but have disadvantages in that hardness and contamination resistance are undesirable. Japanese Patent Application Laid-Open No. 7-18169 discloses a polyester resin prepared by using isophthalic acid and phthalic anhydride as main acid components and using alcohol components having 5 to 6 carbon atoms such as neopentyl glycol and 1,6-hexanediol. It is starting. Although this method is intended to satisfy both hardness and workability at the same time, the hardness of the resin itself is still low, and there is a limit to the improvement in coating film hardness. .

On the other hand, generally used resins, such as polyester, polycarbonate, polystyrene, polyethylene, polypropylene, and styrene acrylic copolymer, are obtained from fossil resources such as petroleum. Recently, in order to cope with the depletion of fossil resources, the increase of atmospheric carbon dioxide due to the large consumption of petroleum resources, and the resulting global warming, efforts have been made to reduce the consumption of fossil resources. For example, the use of a plant-derived resin that grows while releasing carbon dioxide into the atmosphere can help to solve the problem of warming, depletion of petroleum resources, etc. because carbon dioxide is circulated in the environment.

In such an environmentally cyclic resin (polymer), it is desirable to increase the biomass raw material content (biomass amount or bio content). Biomass refers to biological organisms such as plants, microorganisms, cells, and animals that receive solar energy, and biomass materials include starch-based resources such as grains and potatoes, cellulose-based resources such as herbs, wood, rice straw, rice hulls, and candy. Plant-derived environmental cyclic resources such as sugar-based resources such as sorghum and sugar beet, and animal-derived environmental cyclic resources such as livestock manure, dead bodies, and microbial cells, as well as various organic matters such as paper and food waste derived from these resources. Contains waste. Biomass feedstocks are renewable and, unlike fossil fuels, are not depleted, and carbon dioxide released into the atmosphere through combustion is also environmentally friendly, as it is circulated in nature. By combining biological or chemical technology with such biomass raw materials, the biomass raw materials can be utilized as an energy source or a material of various synthetic materials, and can replace conventional petrochemical products.

Therefore, recently, a method of improving the heat resistance of a polyester resin has been developed by using isosorbide, which is a biomass-derived compound derived from starch, as a comonomer of a polyester resin.

[Formula 1]

Since isosorbide is a secondary alcohol, its reactivity is low, and it is known that it is difficult to form a high viscosity polyester used for producing a sheet or a bottle. However, U. S. Patent No. 5,959, 066 discloses a process for melt-polymerizing polyesters having an intrinsic viscosity of 0.35 dl / g or more using various diols including terephthalic acid and isosorbide. Polyester resins with an intrinsic viscosity of 0.35 dl / g or higher are used for optical products and coatings, polyester resins with an intrinsic viscosity of 0.4 dl / g or higher are used for CDs, and polyester resins with an intrinsic viscosity of 0.5 dl / g or higher are used for bottles and films. It can be used for sheet, injection, and the like. U.S. Patent No. 6,063,464 also discloses a method for producing a polyester having a intrinsic viscosity of 0.15 dl / g or more by melt polymerization using a glycol component containing isosorbide. These patents use polyesters to produce polyester using conventional polyester polymerization raw materials, methods and catalysts, while the total content of the biomass-derived compound is kept low.

Accordingly, an object of the present invention is to use a polyester binder resin for coating with a high biomass raw material content and an environmentally friendly coating using isosorbide and lactic acid or a compound derived therefrom which is an environmentally cyclic polymerization raw material derived from a plant. It is to provide a composition.

Another object of the present invention is to provide a polyester binder resin for coating having a high glass transition temperature, not only excellent coating hardness, but also excellent in stain resistance, hydrolysis resistance, processability, and the like, and a coating composition containing the same.

It is still another object of the present invention to provide a polyester binder resin useful for coating can inner surfaces, home appliances, building exterior materials and the like, and a coating composition containing the same.

In order to achieve the above object, the present invention is a diacid component; A diol component comprising 1 to 60 moles of isosorbide relative to the total diol component; And 1 to 50% by weight of lactic acid or a derivative thereof, based on the total resin polymerization reaction, is copolymerized to derive from the diacid moiety derived from the diacid component, the diol moiety derived from the diol component and the lactic acid or derivative thereof Provided is a polyester resin binder for coating having a structure in which the hydroxy monovalent acid moiety is repeated. In addition, the present invention, the polyester resin binder for coating 10 to 60% by weight; And a remaining amount of the organic solvent.

The polyester binder resin and the coating composition according to the present invention are manufactured using the biomass-derived isosorbide and lactic acid or its derivatives at the same time, and thus are environmentally friendly, and have hardness, contamination resistance, hydrolysis resistance, processability and scratch resistance. Since it is possible to form an excellent coating film, it is useful for industrial coating applications, such as coating the inner surface of the can, home appliances, building exterior materials.

Hereinafter, the present invention will be described in detail.

The polyester resin binder for coating according to the present invention is a diacid moiety derived from the diacid component by copolymerizing a diacid component, a diol component and a lactic acid or a derivative thereof. And a diol moiety derived from the diol component and a hydroxy-monoacid moiety derived from the lactic acid or a compound derived from the diol moiety.

The diacid component used in the preparation of the copolymerized polyester resin binder for coating according to the present invention is a dicar selected from the group consisting of an aromatic dicarboxylic acid component having 8 to 14 carbon atoms and an aliphatic dicarboxylic acid component having 4 to 12 carbon atoms. A carboxylic acid component. The aromatic dicarboxylic acid component having 8 to 14 carbon atoms is conventional for the production of polyester resins such as naphthalenedicarboxylic acid, diphenyl dicarboxylic acid, such as terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid. Aromatic dicarboxylic acid component used as the aliphatic dicarboxylic acid component of 4 to 12 carbon atoms, such as 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid Linear, branched or cyclic aliphatic commonly used in the preparation of polyester resins such as hexanedicarboxylic acid, phthalic acid, sebacic acid, succinic acid, isodecyl succinic acid, maleic acid, fumaric acid, adipic acid, glutaric acid, azelaic acid Dicarboxylic acid component. The dicarboxylic acid component may be used alone or in combination of two or more, preferably terephthalic acid, isophthalic acid, mixtures thereof. With respect to the total diacid component, the content of the terephthalic acid and / or isophthalic acid component is preferably 30 to 100 mol%, more preferably 50 to 100 mol%, most preferably 70 to 100 mol%, for example For example, it may be 70 to 99 mol%, 70 to 95 mol% and the like, and the remaining components are other aromatic or aliphatic dicarboxylic acid components except terephthalic acid and / or isophthalic acid. Here, if the content of the terephthalic acid and isophthalic acid component is too small, the Tg of the polyester resin is too low, there is a fear that the hardness after coating is lowered. In the present specification, terms such as terephthalic acid component, terephthalic acid, alkyl esters thereof (lower alkyl esters having 1 to 4 carbon atoms such as monomethyl, monoethyl, dimethyl, diethyl or dibutyl ester) and / or acid anhydrides thereof (acid) It is used in the sense containing an ester-forming derivative component such as anhydride) and reacts with the glycol component to form a terephthaloyl moiety. In the present specification, the diacid moiety, the diol moiety, and the hydroxy monoacid moiety include the diacid moiety, the diol moiety, and the hydroxy monoacid moiety. When polymerized to polyester by condensation reaction, it refers to the residue remaining after the hydrogen, hydroxy group or alkoxy group is removed. Accordingly, the polyester resin according to the present invention has a structure in which a hydroxy monoacid moiety is inserted into a conventional polyester structure in which the diacid moiety and the diol moiety are alternately repeated.

The diol component used in the present invention is (i) 1 to 60 mol%, preferably 10 to 55 mol%, more preferably 30 to 50 mol% of isosorbide (1) based on the total diol component. , 4: 3,6-dianhydroglucitol) and (ii) polyester monomers for ensuring solubility of industrial solvents in ethylene glycol, diethylene glycol, triethylene glycol, propanediol (1,2 Propanediol, 1,3-propanediol, etc.), butanediol (1,4-butanediol, etc.), pentanediol, hexanediol (1,6-hexanediol, etc.), neopentyl glycol (2,2-dimethyl-1, 3-propanediol), 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tetra Methylcyclobutanediol, mixtures thereof, and the like 40 to 99 mol%, preferably 45 to 95 mol%, selected from the group consisting of Innovation and preferably 50 to 95 mol%, and most preferably from 70 to 90 mol%.

Lactic acid or a compound derived thereof used in the present invention is a compound having both acid and alcohol properties, and examples thereof include D-lactic acid, L-lactic acid, and D or L-lactide produced from lactic acid. can do. The content of the lactic acid or the derivative thereof is 1 to 50% by weight, preferably 10 to 45% by weight, more preferably 15 to 40% by weight based on the total resin polymerization reactant. It is preferable to use a large amount of the lactic acid or a compound derived therefrom as long as it does not affect the physical properties (heat resistance, color, etc.) of the coating resin, but when the amount thereof is excessively large, the hardness and solvent solubility of the polyester resin There is a risk of deterioration. In the polyester resin according to the present invention, the content of the biomass raw material component containing the isosorbide and lactic acid or a compound derived therefrom is preferably 5 to 70% by weight based on the total polyester resin polymerization raw material. Preferably it is 20-60 weight%, Most preferably, it is 30-50 weight%, The content of the petroleum origin compound which consists of the diacid component and diol component is 30-95 weight%, Preferably it is 40-80 weight% to be. If the content of the biomass raw material component is less than 5% by weight, there is no meaning of using the biomass raw material, and if it exceeds 70% by weight, solvent solubility, coating property, etc. of the produced polyester resin may be poor.

Next, the manufacturing method of the polyester resin which concerns on this invention is demonstrated. First, (a) a diacid component comprising (i) an aromatic dicarboxylic acid component, an aliphatic dicarboxylic acid component, and the like, (ii) 1 to 60 mol% isosorbide and, for example, 1 to 90 mol% 0.1-3.0 kgf / of a polymerization reaction containing ethylene glycol and diol component containing other glycol components as needed, and (iii) 1-50 weight% of lactic acid or its derived compound with respect to the total resin polymerization reaction product. The esterification reaction or the transesterification reaction is carried out at a pressure of cm 2 and an average residence time of 100 minutes to 10 hours at a temperature of 200 to 300 ° C. (b) Next, the esterification or transesterification product is subjected to a polycondensation reaction under reduced pressure of 400 to 0.1 mmHg and an average residence time of 1 to 10 hours at a temperature of 240 to 300 ° C. Ester resin binder can be manufactured. Preferably, the final attained vacuum degree of the polycondensation reaction is less than 2.0 mmHg, and the esterification reaction and the polycondensation reaction may be performed under an inert gas atmosphere.

Looking specifically at the method for producing a polyester resin according to the present invention, in preparing a copolyester using a diacid component such as terephthalic acid, a diol component such as isosorbide and lactic acid, the diol component for the diacid component The diacid component and the diol component are added so as to have a molar ratio of 1.05 to 3.0, and further 1 to 50% by weight of lactic acid or a derivative thereof is added to the total resin polymerization reaction, and then 200 to 300 ° C, preferably The esterification reaction is carried out at a temperature of 240 to 260 ° C., more preferably 245 to 255 ° C. and a pressurized pressure condition of 0.1 to 3.0 kgf / cm 2, preferably 0.2 to 2.0 kgf / cm 2. Here, when the molar ratio of the diol component / diacid component is less than 1.05, the unreacted acid component may remain during the polymerization reaction and the transparency of the resin may be lowered. This may fall. The esterification reaction time (average residence time) is usually about 100 minutes to 10 hours, preferably about 2 hours to 500 minutes, and may vary depending on the reaction temperature and pressure and the molar ratio of the diol component to the diacid component. When the process of preparing the polyester resin is divided into an esterification reaction (first step) and a polycondensation reaction (second step), the catalyst is not required for the esterification reaction, but a catalyst may be used to shorten the reaction time.

After the said esterification reaction, a polycondensation reaction is performed and a polycondensation catalyst, a stabilizer, etc. can be added to the product of an esterification reaction before starting a polycondensation reaction. As the polycondensation catalyst, one or more of conventional titanium, germanium, antimony, aluminum, tin compound, and the like may be appropriately selected and used. Among these, compared with antimony and titanium catalysts, the use of germanium catalysts has the advantage that the color of the polyester resin is excellent. As a stabilizer added to the polycondensation reaction, phosphorus compounds such as phosphoric acid, trimethyl phosphate and triethyl phosphate can be generally used, and the amount of the additive is 10 to 100 ppm based on the weight of the final polyester based on the amount of phosphorus element. If the addition amount of the stabilizer is less than 10 ppm, the stabilization effect is insufficient, there is a fear that the color of the polymer (polyester) may turn yellow, if the content exceeds 100 ppm there is a fear that the desired high polymerization degree of the polymer may not be obtained. In addition, as a colorant added to improve the color of the polymer, cobalt acetate, generally, the polycondensation reaction is 240 to 300 ℃, preferably 250 to 290 ℃, more preferably 260 to 280 ℃ and 400 to It is carried out under reduced pressure of 0.1 mmHg. The reduced pressure condition is for removing glycol which is a byproduct of the polycondensation reaction. The polycondensation reaction is carried out for the required time, for example for an average residence time of 1 to 10 hours, until the desired intrinsic viscosity is reached. In the polymerization of the polyester according to the present invention, if necessary, in addition to the diacid component, diol component and lactic acid or a derivative thereof, a small amount (for example, 0 to 10 mol% of the total reactants, specifically 0.1 to 10) Molar percent) and / or trihydric alcohol components (e.g., trimellitic acid, trimethylol propane, etc.) may further be used. After dissolving the polyester resin according to the present invention in a concentration of 1.2 g / dl in orthochlorophenol (OCP), when the intrinsic viscosity was measured at 35 ℃, 0.15 dl / g or more, preferably 0.5 dl / g or more Intrinsic viscosity The number average molecular weight (Mn) of the polyester resin binder according to the present invention is generally 2,000 to 20,000, preferably 5,000 to 15,000, and the hydroxyl value is 2 to 60 mgKOH / g, preferably 5 to 50 It is mgKOH / g, the acid value is 0.1 to 20 mgKOH / g, preferably 1 to 5 mgKOH / g, the glass transition temperature (Tg) is preferably 10 to 150 ℃, more preferably 60 to 120 ° C, most preferably 80 to 105 ° C. Here, if the number average molecular weight (Mn) is out of the above range, there is a concern that the physical properties of the coating film is lowered. If the acid value and acid value are too high, poor appearance and popping due to rapid curing at high temperature baking (hardening by heat treatment). There is a risk of phenomenon. In addition, when the glass transition temperature is too high, the workability of the coating film is lowered, and when too low, there is a fear that the coating film hardness is lowered.

The coating composition according to the invention is a solvent-based coating composition, which is 10 to 60% by weight, preferably 15 to 50% by weight, more preferably 20 to 45% by weight based on the total coating composition. % Of the polyester resin binder and the remaining content, preferably 30 to 90% by weight, more preferably 35 to 85% by weight, even more preferably 40 to 71% by weight, most preferably 44 to 64% by weight Organic solvents. Here, if the content of the polyester resin is too small, the viscosity of the paint is excessively lowered, if too much, the viscosity is too high, there is a fear that the coating property is poor. In addition, if necessary, the coating composition according to the present invention comprises 3 to 13% by weight of crosslinking agent, 0.1 to 1.5% by weight of curing catalyst, 0.3 to 10% by weight of slip additive, 0.5 to 1.0% by weight of leveling agent, 0.5 To 1.0% by weight of an antifoaming agent, 0 to 40% by weight, preferably 10 to 30% by weight of the pigment and the like can be further included. Hereinafter, each component of the coating composition will be described item by item.

1. Crosslinking agent

A crosslinking agent forms a coating film (coating film) with a polyester resin binder component, A normal crosslinking agent can be used without a restriction | limiting, For example, a melamine type, an isocyanate type, a carbodiimide type, an epoxy type crosslinking agent, etc. can be used. Can be. As a melamine type crosslinking agent, the melamine resin containing an amino group or butoxy group, and the melamine resin containing a methoxy group can be used. Melamine resins containing amino groups or butoxy groups are advantageous for increasing the hardness of the coating film. However, when an acid catalyst is used, the reaction rate is slightly slower at high temperatures when fired, and the workability is lowered compared to the methoxy melamine resin. On the other hand, when used with an acid catalyst, the methoxy melamine resin has a high curing reaction rate and excellent workability of the coating film, but relatively poor hardness of the coating film. Therefore, in this invention, in order to maintain the balance of the hardness and workability of a coating film, it is preferable to mix and use the said amino type or butoxy type melamine resin and the methoxy type melamine resin in the weight ratio of 0.3-0.5: 1. Do. At this time, when the mixing ratio of the melamine resin of the amino type or the butoxy type is less than 0.3, the workability of the coating film is good, but there is a fear that the surface hardness of the coating film is lowered, and when it exceeds 0.5, the workability of the coating film is poor, and the paint storage There is a fear that the viscosity increases excessively. In the coating composition of the present invention, 2 to 8% by weight of a methyl etherified melamine resin having a methoxy group is used, and 1 to 5% by weight of a melamine resin having an amino group or a butoxy group, and the total of these curing agents is added to the entire coating composition. 3 to 13% by weight relative to. As the methoxy-type melamine resin, CYTEC's CYMEL303, CYMEL 301, BIP's BE 3747, BE 3745, Monsanto's RESIMENE 745, etc. can be used. As the resin, CYMEL 325, CYMEL327 from CYTEC, BE3748, BE 3040 from BIP, RESIMENE 717 from Monsanto and the like can be used. Besides, ordinary isocyanate-based, carbodiimide-based and epoxy-based curing agents can be used as the crosslinking agent. If the amount of the crosslinking agent is too small, the coating film may not be sufficiently cured, and the coating film properties such as solvent resistance and hardness may be poor, and even if the amount of the crosslinking agent is used too much, it may act as a foreign material, resulting in poor overall coating film properties. have.

2. Curing Catalyst

The curing catalyst that can be used in the coating composition of the present invention is for promoting the curing of the coating film, can be used without limitation conventional curing catalyst, preferably, sulfonic acid-based, amine-based, tin-based curing catalyst can be used For example, neutralized sulfonic acids such as p-toluene sulfonic acid (p-TSA), dinonylnaphthalene sulfonic acid (DNNSA), dinaphthalene disulfonic acid (DNNDSA), and fluoro sulfonic acid with amine or epoxy may be used. The amine and the epoxy are added for the reaction shielding of the catalyst, and as the amine, primary amine, secondary amine, tertiary amine and the like can be used. In general, it is preferable to use a secondary amine because the primary amine causes a color change such as yellowing in the coating film, and the tertiary amine causes shrinkage of the surface of the coating film when used in excess. Examples of the secondary amines include diethylamine, diisopropylamine, diisopropanolamine, di-n-propylamine, di-n-butylamine, diisobutylamine, di-secondary-butylamine, diallylamine , Diamylamine, N-ethyl-1,2-dimethylpropylamine, N-methylhexylamine, di-n-octylamine, piperidine, 2-pipecoline, 3-piecholine, 4-piecoline And morpholine, and by adding these effective amounts to the coating composition, the fouling resistance of the coating film can be increased. If a catalyst not neutralized with amine or epoxy is used, the viscosity may increase after storage of the paint, or the physical properties of the coating may be poor. Commercially available examples of p-toluene sulfonic acid include King's NACURE2500, NACURE2510, NACURE 2530, and the like. The sulfonic acid includes 3M FC520. In addition, p-toluene sulfonic acid, dinonylnaphthalenesulfonic acid (DNNSA), etc. neutralized with tertiary amine can also be used as an auxiliary curing catalyst. The curing catalyst is contained in the range of 0.1 to 1.5% by weight based on the total coating (paint) composition. If the amount of the curing catalyst used is too small, the curing time is long, so that coating film properties such as sufficient hardness cannot be obtained. If the amount of the curing catalyst is used too much, it may act as a foreign matter, thereby degrading the overall coating film properties.

3. Solvent

The coating composition of this invention contains an organic solvent in consideration of handleability, coating workability, etc. As the organic solvent, it is possible to disperse the polyester resin and other components, and can be easily removed without limitation, for example, aromatic hydrocarbons, glycol esters, glycol ethers, ketones, alcohol solvents Etc. can be used alone or in combination. The aromatic hydrocarbon solvents include toluene, xylene (xylene), cocosol (# 100, # 150), etc. of SK Energy, and the glycol ester solvents include ethyl acetate, (n-) butyl acetate, and cellosolve. Acetate, propylene glycol monomethyl acetate, ethylene glycol diacetate, ethylene glycol diethyl ether, ethylene glycol dimethyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether, 3-methoxybutyl acetate and the like can be exemplified. The glycol ether solvents include methyl cellosolve, ethyl cellosolve, ethylene glycol butyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol butyl ether, and the like. Ketone solvents include acetone and acetonitrile. , Methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and the like, and alcohol solvents include ethanol, isopropanol, n-butanol, amyl alcohol, cyclohexanol, and the like, and others, chloroform, cresol, hexane , Tetrahydrofuran, isophorone, dibasic ethers and the like can also be used. The solvent constitutes the remaining components of the entire coating composition. If the amount of the solvent is too small, there is a concern that the adhesion of the coating film may be lowered. If the solvent is too large, the solvent may take a long time to dry.

4. Other additives

The slip additive that may be included in the coating composition of the present invention is to prevent scratches caused by scratches by an operator or nails of a home appliance user during molding, without limiting a conventional slip additive. For example, polyethylene (PE) wax, polytetrafluoroethylene (PTFE) wax, PTFE / PE mixed wax, or the like can be used. It is preferable that the usage-amount of the said polyethylene-type wax is 3 to 5 weight% with respect to the whole coating composition, and when it is less than the said range, there exists a possibility that sufficient slip property may not be provided to a coating film, and when it exceeds the said range, the glossiness of a coating film This may fall. When the PTFE wax is used, the hardness of PTFE itself is excellent, but the specific gravity of PTFE is higher than that of the resin, the orientation to the surface during the curing of the coating is slow, the melting point of PTFE is high, the coating appearance is rough, and the slip performance is well exhibited. There is a risk of not being. Therefore, a mixed wax of PTFE and PE is preferable, because the PE wax has excellent surface orientation, but has a poor slip effect, and PTFE has a good slip effect, but has a problem in surface orientation. It is possible to combine. These PTFE / PE mixed waxes must be made with a high speed disperser to obtain a product in which PTFE wax is attached around a low density PE wax, ie, a product in which PTFE wax is electrostatically combined around a PE wax with a large particle size. . Although the coating film using such a mixed wax is excellent in hardness and sufficient slip property can be obtained, when the PTFE / PE wax particles are too large, the appearance of the coating film is poor, and therefore it is preferable to have a particle size of 3 µm or less. If the slip additive is used in excess, the gloss of the coating film may be lowered. Commercially available products of the wax include MPI-31 and F-600XF of Micro Powder Co., Ltd., Ceraflour 995, 996 from BYK Co., Ltd., SL-524, SL of Daniel Products Co., Ltd. -409 and so on. On the other hand, when the conventional silicone oils are used as slip additives, the surface tension of the silicone oils is too low, the continuous roll coating workability is poor, it is not preferable. In addition, 0.1 to 1% by weight of additives such as clay, amide wax and fume silica may be used to improve workability.

In addition, in order to maintain the coating film smoothness and to improve the defoaming property during painting work, conventional acrylic, vinyl or silicone leveling agents and antifoaming agents can be used. Commercially available examples of such leveling agents and antifoaming agents may include Disparon L-1980, Disparon L-1984, Disparon AP-30, BYK356 by BYK356 and BYK410 by Kusumoto Chemical. In addition, the coating composition of the present invention may be used as a transparent coating composition containing no pigment, but may be used as a color coating composition containing a coloring pigment. As the coloring pigment, organic coloring pigments such as cyanine blue, cyanine green, and any coloring pigments usable in the field of coating compositions, and inorganic coloring pigments such as titanium oxide, iron oxide, carbon black, chrome yellow and various plastic pigments can be used. In addition, the coating composition of the present invention may include a sieving pigment, such as talc, clay, silica, mica, alumina, metal or nonmetal filler. When the usage-amount of the said pigment is excessively large, there exists a possibility that the adhesiveness of a dry coating film, the dispersibility of a pigment, etc. may fall.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The following examples are intended to illustrate the invention, but the scope of the invention is not limited by these examples. In the following Examples and Comparative Examples, unless otherwise specified, the unit "parts" or "%" means "parts by weight" or "% by weight", TPA is terephthalic acid, and IPA isophthalic acid ( isophthalic acid), AA is adipic acid, TMA is trimellitic acid, ISB is isosorbide (1,4: 3,6-dianhydroglucitol), EG is ethylene glycol , NPG represents neopentyl glycol (neopentylglycol), TMP represents trimethylol propane, Lactide represents L-lactide, and the method for evaluating the performance of the polymer and the coating composition is as follows.

(1) Intrinsic Viscosity (IV): After dissolving the polymer in a concentration of 0.12% in orthochlorophenol at 150 ° C, it was measured using a Ubelrod viscometer in a constant temperature bath at 35 ° C.

(2) Heat resistance (Tg): By glass-rubber transition temperature (Tg), the Tg temperature in 2nd scan is measured at the temperature increase rate of 10 degreeC / min.

(3) Number average molecular weight: Gas chromatography was used, polystyrene was used as a standard, and co-polyester resin was dissolved in tetrahydrofuran and measured.

(4) Bio content (%): Using the 600 Mhz nuclear magnetic resonance (NMR) spectrometer, the content of each component of the biomass polymerization raw material is measured and combined in the resin.

(5) Magic contamination: A coating composition (coating) is coated on a galvanized steel sheet having a thickness of 0.5 mm, and dried at 270 ° C. for 50 seconds with a hot air dryer to prepare a coated steel sheet. After drawing a line using a red, blue, and black oil-based magic to the steel sheet prepared, and after 30 minutes was wiped with a gauze soaked in xylene (xylene), it was observed whether the traces remain.

(6) Pencil hardness: The coating film hardness was measured with Mitsubishi pencil about the same coated steel plate as used in the "magic contamination" item.

(7) Machinability: When the same coated steel sheet used in the above "Magic contamination" item is bent completely by bending 180 degrees with a steel plate of the same thickness therebetween, it is observed with a magnification of 30 times, so that no cracking of the coating film occurs. It measured by the number of the steel sheets inserted when it was not.

(8) Accelerated weather resistance: After 7,000 hours of tests on the same coated steel plate as used in the item "Magic contamination" above on a QUV accelerated weather resistance tester (produced by Q-Pannel), the gloss retention rate was determined by% of initial gloss. Represented by. The accelerated weathering conditions used a cycle of condensation at 50 ° C. for 4 hours and QUV-A (340 nm) UV irradiation at 8 hours at the same temperature.

[Examples 1-3 and Comparative Examples 1-2]

A. Preparation of Copolyester

In the composition shown in Table 1 below, the acid component and the alcohol component were placed in a 500 ml three-necked flask, 200 ppm of a germanium catalyst and 70 ppm of a phosphate stabilizer were added thereto, followed by applying a heat of 240 to 300 ° C. to proceed with the esterification reaction. It was. The polycondensation reaction proceeded when the by-product water flowed out of the system 70 to 99%, and the polymerization was terminated when a certain viscosity was reached. The input amounts of the catalyst and stabilizer are each added in ppm units relative to the total raw material input amount on the basis of the central element of the catalyst and stabilizer molecules. The characteristic of the obtained polyester was measured and shown in Table 1 together.

Table 1

B. Preparation of Paint

Cellulose acetate / cyclohexanone / Solvesso # 150 (30/30/40, mass ratio) was dissolved in a mixed solvent of copolyester resins prepared in Examples and Comparative Examples, and the solid content of 50% by weight The resin solution was prepared, and the dispersion compound phase shown in Table 2 was prepared using the same, and the dissolution compounding shown in Table 3 was carried out to prepare a coating composition.

TABLE 2

TABLE 3

C. Evaluation of coating film properties : The prepared coating material was coated on a steel sheet to measure coating film properties, and the results are shown in Table 4 below.

Table 4

From the above Table 4, the polyester binder resin and the coating composition according to the present invention, while containing a large amount of isosorbide and lactic acid or a derivative thereof derived from biomass, hardness, stain resistance, hydrolysis resistance, processability, scratch resistance It can be seen that an excellent coating film is formed.

The polyester binder resin and the coating composition according to the present invention are useful for industrial coating applications such as can inner surface, home appliance, and building exterior coating.

Claims (9)

1. Diacid component; Diol component containing 1-60 mol of isosorbides with respect to a total diol component; And 1 to 50% by weight of lactic acid or a derivative thereof, based on the total resin polymerization reactant,

   A polyester resin binder for coating having a structure in which a diacid portion derived from the diacid component, a diol portion derived from the diol component, and a hydroxy monoacid portion derived from the lactic acid or a derivative thereof are repeated.
2. The petroleum product according to claim 1, wherein the content of the biomass raw material component containing the isosorbide and lactic acid or a derivative thereof is 5 to 70% by weight based on the total resin polymerization reactant, and the diacid component and the diol component. The content of the resource-derived compound is 30 to 95% by weight, the coating polyester resin binder.
3. The coating polyester resin binder according to claim 1, wherein the lactic acid or a compound thereof is selected from the group consisting of D-lactic acid, L-lactic acid, D-lactide and L-lactide.
4. The coating polyester resin binder according to claim 1, wherein the polyester resin is copolymerized with a triacid and / or a trihydric alcohol component of 0 to 10 mol% based on the total reactants.
5. According to claim 1, wherein the diol component is ethylene glycol, diethylene glycol, triethylene glycol, propanediol (1,2-propanediol, 1,3-propanediol, etc.), 1,4-butanediol, pentanediol, hexane Diols (such as 1,6-hexanediol), neopentyl glycol (2,2-dimethyl-1,3-propanediol), 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclo Hexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tetramethylcyclobutanediol, 40 to 99 mol% glycol selected from the group consisting of a mixture thereof, for coating Polyester resin binder.
6. The method of claim 1, wherein the polyester resin has a number average molecular weight (Mn) of 2,000 to 20,000, a hydroxyl value of 2 to 60 mgKOH / g, an acid value of 0.1 to 20 mgKOH / g, the glass transition temperature (Tg) Is 10 to 150 ℃, polyester resin binder for coating.
7. 10 to 60% by weight of the polyester resin binder for coating according to any one of claims 1 to 6; And

   A coating composition comprising the remaining amount of organic solvent.
8. 8. The coating composition of claim 7, wherein the organic solvent is selected from the group consisting of aromatic hydrocarbons, glycol esters, glycol ethers, ketones, alcohols, and mixtures thereof.
9. The method according to claim 7, 3 to 13% by weight crosslinking agent, 0.1 to 1.5% by weight curing catalyst, 0.3 to 10% by weight slip additive, 0.5 to 1.0% by weight leveling agent, 0.5 to 1.0% by weight antifoaming agent, And 0 to 40% by weight of a pigment.